CN114685846B - Supercritical decrosslinking pretreatment rubber powder and rubber powder modified asphalt and preparation method thereof - Google Patents
Supercritical decrosslinking pretreatment rubber powder and rubber powder modified asphalt and preparation method thereof Download PDFInfo
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- 229920001971 elastomer Polymers 0.000 title claims abstract description 134
- 239000000843 powder Substances 0.000 title claims abstract description 128
- 239000010426 asphalt Substances 0.000 title claims abstract description 96
- 238000002360 preparation method Methods 0.000 title claims abstract description 15
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 34
- 238000003756 stirring Methods 0.000 claims abstract description 24
- 238000000034 method Methods 0.000 claims abstract description 18
- 238000006243 chemical reaction Methods 0.000 claims abstract description 17
- 239000011159 matrix material Substances 0.000 claims abstract description 17
- 239000000203 mixture Substances 0.000 claims abstract description 15
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 14
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 14
- 239000003431 cross linking reagent Substances 0.000 claims abstract description 11
- 230000008569 process Effects 0.000 claims abstract description 10
- 235000011089 carbon dioxide Nutrition 0.000 claims abstract description 6
- 238000002156 mixing Methods 0.000 claims abstract description 6
- 238000007789 sealing Methods 0.000 claims abstract description 5
- 230000009471 action Effects 0.000 claims abstract description 4
- 238000010438 heat treatment Methods 0.000 claims abstract description 4
- 238000010907 mechanical stirring Methods 0.000 claims abstract description 3
- 238000004132 cross linking Methods 0.000 claims description 27
- GUUVPOWQJOLRAS-UHFFFAOYSA-N Diphenyl disulfide Chemical group C=1C=CC=CC=1SSC1=CC=CC=C1 GUUVPOWQJOLRAS-UHFFFAOYSA-N 0.000 claims description 6
- 238000013461 design Methods 0.000 claims description 4
- 238000005485 electric heating Methods 0.000 claims description 3
- 230000000630 rising effect Effects 0.000 claims description 2
- 239000007787 solid Substances 0.000 claims description 2
- -1 solid carbon dioxide Chemical compound 0.000 claims 1
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- 238000010276 construction Methods 0.000 abstract description 7
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- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J11/00—Recovery or working-up of waste materials
- C08J11/04—Recovery or working-up of waste materials of polymers
- C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
- C08J11/18—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material
- C08J11/28—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic compounds containing nitrogen, sulfur or phosphorus
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L95/00—Compositions of bituminous materials, e.g. asphalt, tar, pitch
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2319/00—Characterised by the use of rubbers not provided for in groups C08J2307/00 - C08J2317/00
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/62—Plastics recycling; Rubber recycling
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Abstract
Supercritical decrosslinking pretreatment rubber powder and rubber powder modified asphalt and a preparation method thereof. The preparation method of the supercritical decrosslinking pretreatment rubber powder comprises the following steps: uniformly mixing rubber powder, a crosslinking agent and dry ice, placing the mixture in a sealed high-pressure reaction kettle, electrifying and heating the mixture to enable carbon dioxide in the high-pressure reaction kettle to be heated and pressurized to reach a supercritical state, and adopting a magnetic sealing stirring paddle in a supercritical carbon dioxide environment to enable the rubber powder and the crosslinking agent to fully and uniformly react to obtain the supercritical crosslinking-removing pretreatment rubber powder. The supercritical decrosslinking pretreatment rubber powder is mixed into the matrix asphalt preheated to flow state, so that the supercritical decrosslinking pretreatment rubber powder and the matrix asphalt are fully and interactively mixed under the action of high-speed mechanical stirring to obtain the supercritical decrosslinking pretreatment rubber powder modified asphalt. The invention obviously improves the uniformity and efficiency of the internal decrosslinking pretreatment process of the rubber powder, and enhances the compatibility between the waste tire rubber powder and the matrix petroleum asphalt, thereby improving the storage stability, construction workability and environmental friendliness of the rubber powder modified asphalt.
Description
Technical Field
The invention belongs to the technical field of modified asphalt for roads, and particularly relates to supercritical uncrosslinking pretreatment rubber powder and rubber powder modified asphalt and a preparation method thereof.
Background
The waste tire rubber is reasonably recycled, so that the problem of environmental pollution caused by the waste tire rubber can be effectively solved, the defect of insufficient natural rubber resources in China can be overcome, and the sustainable development of the rubber industry is promoted. At present, rubber powder modified asphalt (also called rubber asphalt) prepared by using waste tire rubber particles (namely waste tire rubber powder) as a modifier is widely applied to the construction of high-grade asphalt pavement at home and abroad. However, the rubber powder modified asphalt prepared by the conventional wet method has the following problems in practical engineering: (1) The compatibility of the rubber powder modifier and the matrix asphalt is poor, and the rubber powder modifier and the matrix asphalt are easy to separate, so that the storage stability of the rubber powder modified asphalt is poor; (2) The viscosity of the rubber powder modified asphalt is high, so that the construction workability is poor, and the high mixing amount of the rubber powder modifier cannot be realized; (3) The high viscosity characteristic of the rubber powder modified asphalt further leads to higher construction temperature, and a large amount of smoke is released in the stirring, paving and rolling processes of asphalt pavement construction, so that the environment friendliness is poor.
Therefore, there is a need to solve the above-mentioned problems exposed to the application of the gum powder pretreatment in the modification of road asphalt. According to related researches and engineering experience, when the rubber powder is used as an asphalt modifier, the ideal pretreatment process achieves the following effects: (1) The cross-linking bonds in the rubber powder are broken as completely as possible, and the three-dimensional cross-linking network structure in the rubber powder is destroyed, so that the compatibility between the rubber powder and asphalt is improved, and the rubber powder and asphalt can undergo full physical-chemical reaction, so that the purposes of reducing viscosity and inhibiting smoke are achieved; (2) Avoiding the fracture of the rubber main chain in the rubber powder as far as possible, and keeping the toughening effect of the rubber main chain so as to improve the low-temperature flexibility of the rubber powder modified asphalt.
That is, the rubber powder needs to be fully de-crosslinked when used as an asphalt modifier, but should be prevented from being degraded, which requires an efficient and controllable targeted de-crosslinking pretreatment process. Currently, in the field of asphalt polymer modification, the main rubber powder crosslinking methods can be divided into three major categories, namely a physical method, a chemical method and a biological method.
(1) The physical method comprises the following steps: physical methods, such as microwave radiation, ultrasonic radiation and mechanical extrusion, can provide certain external energy, and heat is transferred from outside to inside by means of heat conduction to promote the fracture of crosslinking bonds inside the rubber powder, and the methods are essentially operated by increasing the temperature. However, the high temperature (250 ℃ to 300 ℃) action in the physical decrosslinking process often comes at the cost of fracture of a main chain of the rubber C-C, the high molecular quality of the rubber powder after pretreatment cannot be ensured, the high temperature mechanical property of the prepared rubber powder modified asphalt is affected, and the high temperature treatment causes serious environmental pollution and energy consumption problems.
(2) The chemical method comprises the following steps: the chemical method is to make the rubber powder react with chemical auxiliary agent in organic solvent under certain temperature and pressure, directionally catalyze and break the crosslinking bond in the vulcanized rubber powder, and perform end-capping function to obtain stable breaking point, thereby achieving the purpose of internal decrosslinking. Although the chemical auxiliary agent can selectively break the sulfur bond, the crosslinking reaction of the rubber powder belongs to the solid phase reaction of a complex system, the chemical agent is difficult to permeate and disperse into a crosslinking network in the vulcanized rubber powder, and the uniformity of the inside and the outside of the crosslinking pretreatment cannot be ensured, so that the expected effect cannot be achieved when the crosslinking agent is used for preparing the rubber powder modified asphalt.
(3) The biological method comprises the following steps: certain microbial bacteria take sulfur as a nutrient source, can selectively break C-S and S-S bonds, but have no effect on a C-C structure, so that the microbial bacteria can be used for realizing the biological crosslinking pretreatment of the rubber powder. In fact, however, only a few bacterial strains are able to carry out the desulfurization of the gums. In addition, since the surface of the rubber powder has lipophilicity, microorganisms are hydrophilic, and the affinity of the microorganisms and the microorganisms is poor. Thus, during the de-crosslinking process, the microorganisms and their desulphurases cannot act effectively on the surface of the gelatine powder. On the other hand, toxic additives in the gum powder tend to result in lower microbial survival rates. Therefore, the biological method is long in time consumption and far lower in efficiency than the other two methods, and the defects can not meet the requirement of high-efficiency industrial production of the road rubber powder modified asphalt.
In summary, the existing means cannot well achieve the purpose of efficiently and controllably targeted de-crosslinking the waste tire rubber powder, so that the waste tire rubber powder used as an asphalt modifier for preparing the road rubber powder modified asphalt still has a plurality of inherent defects, and therefore, a new rubber powder pretreatment means needs to be considered.
Disclosure of Invention
The invention aims to provide supercritical decrosslinking pretreatment rubber powder and rubber powder modified asphalt and a preparation method thereof. Considering that the existing means can not well achieve the purpose of efficiently and controllably targeted de-crosslinking of the waste tire rubber powder (used as a road asphalt modifier), new means are needed to be considered. The supercritical fluid technology is introduced into the invention as a new means for pretreatment of the rubber powder modifier. In general, supercritical fluids have both gas permeability and liquid solubility. Therefore, the supercritical fluid is an ideal reaction medium for the crosslinking of the rubber powder, can be used as a swelling agent and a carrying agent at the same time, and helps to realize the efficient controllable targeted crosslinking pretreatment of the rubber powder.
The first object of the invention is to provide a preparation method of supercritical de-crosslinking pretreatment rubber powder, the second object is to provide a preparation method of supercritical pretreatment rubber powder modified asphalt, and the third object is to provide supercritical pretreatment rubber powder modified asphalt.
The aim of the invention can be achieved by the following technical scheme:
a preparation method of supercritical decrosslinking pretreatment rubber powder comprises the following steps:
(1) Uniformly mixing rubber powder, a crosslinking agent and dry ice (solid carbon dioxide), and placing the mixture in a sealed high-pressure reaction kettle;
(2) And (3) electrifying and heating to heat and pressurize carbon dioxide in the high-pressure reaction kettle to reach a supercritical state, and adopting a magnetic sealing stirring paddle in a supercritical carbon dioxide environment to fully and uniformly react the rubber powder with the crosslinking agent to obtain the supercritical crosslinking pre-treatment rubber powder.
Preferably, in the step (1), the rubber powder is rubber particles prepared by crushing waste tires at normal temperature or low temperature, and the particle size range is 30-80 meshes.
Preferably, in step (1), the cross-linking agent is Diphenyl Disulfide (DD) and the purity is analytically pure.
Preferably, in the step (1), the mass ratio of the crosslinking agent to the rubber powder is 5:100 to 35:100.
Preferably, in step (1), the purity grade of the dry ice reaches a food grade, and the purity is higher than 99.99%.
Preferably, in the step (1), in the technical parameter indexes of the high-pressure reaction kettle, the design temperature and the working temperature are respectively not lower than 300 ℃ and 250 ℃, the design pressure and the working pressure are respectively not lower than 15MPa and 20MPa, and the volume is not lower than 1L.
Preferably, in the step (2), the temperature rising rate of the high-pressure reaction kettle under external electric heating is not lower than 5 ℃/min.
Preferably, in the step (2), the density of supercritical carbon dioxide in the high-pressure reaction kettle in the process of the rubber powder crosslinking pretreatment is not lower than 0.16g/cm 3, the temperature is not lower than 200 ℃, and the pressure is not lower than 8MPa.
Preferably, in the step (2), the stirring speed of the magnetic sealing stirring paddle is not less than 150rpm.
Preferably, in step (2), the duration of the pre-treatment reaction for the crosslinking of the gum powder is not shorter than 1h.
A preparation method of supercritical decrosslinking pretreatment rubber powder modified asphalt comprises the following steps:
The supercritical decrosslinking pretreatment rubber powder is mixed into the matrix asphalt preheated to flow state, so that the supercritical decrosslinking pretreatment rubber powder and the matrix asphalt are fully and interactively mixed under the action of high-speed mechanical stirring to obtain the supercritical decrosslinking pretreatment rubber powder modified asphalt. Wherein the supercritical decrosslinking pretreatment rubber powder is prepared by the preparation method of the supercritical decrosslinking pretreatment rubber powder.
Preferably, the preheating temperature of the matrix asphalt is 170 ℃ to 175 ℃ and the preheating time is not shorter than 2 hours.
Preferably, the mass ratio of the supercritical decrosslinking pretreatment rubber powder to the matrix asphalt is 15:100 to 35:100.
Preferably, the stirring temperature is 175 ℃ to 180 ℃, the stirring speed is 1000rpm to 1500rpm, and the stirring time is 30min to 45min.
The supercritical decrosslinking pretreatment rubber powder modified asphalt is prepared by the preparation method of the supercritical decrosslinking pretreatment rubber powder modified asphalt.
Compared with the prior art, the invention has the following characteristics:
(1) Compared with common rubber powder, the supercritical decrosslinking pretreatment rubber powder prepared by the invention has the advantages that the sol rate is obviously improved, the crosslinking density is obviously reduced, the surface is rougher, and meanwhile, the high relative molecular weight of the rubber main chain can be maintained. When the modified asphalt is used as an asphalt modifier, the compatibility between the waste tire rubber powder and the matrix asphalt can be effectively enhanced by the characteristics, the high-mixing-amount application of the rubber powder in the modified asphalt for road is realized, and the recycling rate of the waste tires in the field of road engineering is further improved.
(2) Compared with the common rubber powder modified asphalt, the supercritical decrosslinking pretreatment rubber powder modified asphalt prepared by the invention has obviously improved storage stability, low-temperature flexibility, ageing resistance and fatigue resistance, and simultaneously has reduced viscosity, thereby being beneficial to reducing the emission of high-temperature asphalt smoke. The characteristics can relieve the problem that the application of the rubber powder modified asphalt in actual engineering is limited.
(3) The preparation method of the supercritical decrosslinking pretreatment rubber powder and the rubber powder modified asphalt has the characteristics of simple process, obvious effect and controllable process, and all required equipment is industrial equipment with mature technology, so that the preparation method has the prospect of mass production.
Detailed Description
The present invention will be described in detail with reference to specific examples and comparative examples. The present embodiment is implemented on the premise of the technical scheme of the present invention, and a detailed implementation manner and a specific operation process are given, but the protection scope of the present invention is not limited to the following examples.
Example 1:
Step 1, 100g of waste truck tire rubber powder (40 meshes) and 15g of analytical grade Diphenyl Disulfide (DD) crosslinking agent are evenly mixed and then put into a high-pressure reaction kettle.
And 2, putting 200g of food-grade dry ice into the kettle, and rapidly closing the kettle cover to screw the screw. And sublimating the dry ice in the kettle into carbon dioxide by adopting external electric heating, and gradually heating and pressurizing to reach a supercritical carbon dioxide fluid state. The supercritical carbon dioxide is at 250 ℃, the pressure is 9MPa, the stirring speed of the magnetic sealing stirring paddle is 300rpm, the duration of the decrosslinking reaction is 2h, and the supercritical decrosslinking pretreatment rubber powder is prepared in a supercritical carbon dioxide environment. The sol content of the prepared supercritical decrosslinking pretreatment rubber powder is 37.2%, and the gel crosslinking density is 6.3 x 10 -5mol/cm3.
Example 2:
70g of the supercritical decrosslinking pretreatment rubber powder (40 meshes) prepared by the method of the reference example 1 is mixed into 200g of Beijing bo 70 # petroleum base asphalt preheated to 170 ℃ and stirred continuously for 45min under the conditions of a stirring temperature of 175 ℃ and a stirring speed of 1000rpm, so that the supercritical decrosslinking pretreatment rubber powder modified asphalt with high mixing amount (externally mixing 35%) is prepared. The performance test results of the prepared high-doping amount supercritical uncrosslinking pretreatment rubber powder modified asphalt are shown in table 1, and each performance of the prepared high-doping amount supercritical uncrosslinking pretreatment rubber powder modified asphalt can meet the requirements of the modified asphalt for road use.
TABLE 1 Performance test results of high blend supercritical Decrosslinking Pre-treated rubber powder modified asphalt
Comparative example 1:
30g of supercritical decrosslinking pretreatment rubber powder (40 meshes) is mixed into 200g of Beijing bo No. 70 petroleum matrix asphalt preheated to 170 ℃, and the mixture is continuously stirred for 45min under the conditions of the stirring temperature of 175 ℃ and the stirring speed of 1000rpm, so that the supercritical decrosslinking pretreatment rubber powder modified asphalt with 15% of the mixture is prepared. 30g of common rubber powder (40 meshes) is mixed into 200g of Beijing bo 70 # petroleum base asphalt preheated to 170 ℃, and the mixture is continuously stirred for 45min under the conditions of the stirring temperature of 175 ℃ and the stirring speed of 1000rpm, so that the common rubber powder modified asphalt with 15 percent of the mixed mixture is prepared. According to the test specification of highway engineering asphalt and asphalt mixture (JTG E20-2011), a polymer modified asphalt segregation test method is adopted, and the storage stability of the supercritical de-crosslinking pretreatment rubber powder modified asphalt and the storage stability of the common rubber powder modified asphalt are respectively compared by taking the difference of softening points and segregation rate as evaluation indexes. As shown in Table 2, the segregation degree of the common rubber powder modified asphalt is remarkably higher, and compared with the supercritical decrosslinking pretreatment rubber powder modified asphalt, the common rubber powder modified asphalt has more excellent storage stability.
TABLE 2 results of storage stability comparisons of supercritical De-crosslinking Pre-treated rubber modified asphalt and Normal rubber modified asphalt
Comparative example 2:
30g of supercritical decrosslinking pretreatment rubber powder (40 meshes) is mixed into 200g of Beijing bo No. 70 petroleum matrix asphalt preheated to 170 ℃, and the mixture is continuously stirred for 45min under the conditions of the stirring temperature of 175 ℃ and the stirring speed of 1000rpm, so that the supercritical decrosslinking pretreatment rubber powder modified asphalt with 15% of the mixture is prepared. 30g of common rubber powder (40 meshes) is mixed into 200g of Beijing bo 70 # petroleum base asphalt preheated to 170 ℃, and the mixture is continuously stirred for 45min under the conditions of the stirring temperature of 175 ℃ and the stirring speed of 1000rpm, so that the common rubber powder modified asphalt with 15 percent of the mixed mixture is prepared. According to the test specification of asphalt and asphalt mixture for highway engineering (JTG E20-2011), the construction workability of the supercritical de-crosslinking pretreatment rubber powder modified asphalt and the common rubber powder modified asphalt is compared by adopting an asphalt Brookfield viscometer test method and using 135 ℃ rotational viscosity as an evaluation index. The rotational viscosity of the supercritical decrosslinking pretreatment rubber powder modified asphalt at 135 ℃ is 2.53Pa s, the rotational viscosity of the common rubber powder modified asphalt at 135 ℃ is 6.68Pa s, the common rubber powder modified asphalt is not easy to pump and pave, and compared with the common rubber powder modified asphalt, the supercritical decrosslinking pretreatment rubber powder modified asphalt has more excellent construction workability.
The previous description of the embodiments is provided to facilitate a person of ordinary skill in the art in order to make and use the present invention. It will be apparent to those skilled in the art that various modifications can be readily made to these embodiments and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above-described embodiments, and those skilled in the art, based on the present disclosure, should make improvements and modifications without departing from the scope of the present invention.
Claims (2)
1. A supercritical uncrosslinking pretreatment rubber powder modified asphalt is characterized in that:
The supercritical decrosslinking pretreatment rubber powder is mixed into matrix asphalt which is preheated to completely flow, so that the supercritical decrosslinking pretreatment rubber powder and the matrix asphalt are fully mixed and dissolved under the action of high-speed mechanical stirring to obtain supercritical decrosslinking pretreatment rubber powder modified asphalt;
Wherein the preheating temperature of the matrix asphalt is 170 ℃ to 175 ℃ and the preheating time is not shorter than 2 h;
the mass ratio of the supercritical decrosslinking pretreatment rubber powder to the matrix asphalt is 35:100;
The preparation method of the supercritical decrosslinking pretreatment rubber powder comprises the following steps:
(1) Uniformly mixing 100 g meshes of rubber powder, 15 g crosslinking agent and 200g of dry ice, namely solid carbon dioxide, and placing the mixture in a sealed high-pressure reaction kettle;
(2) Heating by electrifying to heat and pressurize the carbon dioxide in the high-pressure reaction kettle to reach a supercritical state, and adopting a magnetic sealing stirring paddle in a supercritical carbon dioxide environment to fully and uniformly react the rubber powder with the crosslinking agent to obtain supercritical crosslinking pretreatment rubber powder;
wherein the de-crosslinking agent is diphenyl disulfide;
The design temperature and the working temperature of the high-pressure reaction kettle are respectively not lower than 300 ℃ and 250 ℃, the design pressure and the working pressure are respectively not lower than 15 MPa and 20 MPa, and the volume is not lower than 1L;
The temperature rising rate of the high-pressure reaction kettle under external electric heating is not lower than 5 ℃ per minute;
The density of supercritical carbon dioxide in a high-pressure reaction kettle is not lower than 0.16 g/cm 3, the temperature is not lower than 200 ℃ and the pressure is not lower than 8 MPa in the process of the crosslinking pretreatment of the rubber powder;
The sol content of the prepared supercritical decrosslinking pretreatment rubber powder is 37.2%, and the gel crosslinking density is 6.3 x 10 -5 mol/cm3.
2. The modified asphalt of claim 1, wherein the supercritical de-crosslinked pre-treated asphalt is blended into a fully-fluidized matrix asphalt at a stirring temperature of 175 ℃ to 180 ℃, a stirring rate of 1000 rpm to 1500 rpm, and a stirring time of 30min to 45 min.
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| CN110079106A (en) * | 2019-04-26 | 2019-08-02 | 同济大学 | A kind of dissolubility rubber powder modified asphalt of high-storage stability |
| WO2021013011A1 (en) * | 2019-07-19 | 2021-01-28 | 长安大学 | Use of waste engine oil for modifying rubber |
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| WO2021013011A1 (en) * | 2019-07-19 | 2021-01-28 | 长安大学 | Use of waste engine oil for modifying rubber |
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